More and more implantable sensors are being used, developed, or proposed. Such implantable sensors can be used to detect physiologic, cardiac and other related parameters of a patient for the purpose of monitoring such parameters and/or using such parameters as feedback for adjusting other parameters of implantable devices, such as for adjusting pacing parameters of pacemakers. However, many such implantable sensors are sensitive to a patient's body position and/or body movement. Examples of such implantable sensors include photoplethysmography (PPG) sensors, left atrial pressure (LAP) sensors, impedance sensors and cardio-mechanical sensors (CMES), but are not limited thereto.
Data collected by an implantable sensor that is sensitive to body position and/or body movement may provide inaccurate readings, which can adversely affect its monitoring and/or feedback capabilities. For example, determinations of patient condition status and alarms that are based on such sensor readings can become inaccurate, resulting in incorrect adjustments to sensor-based therapy and/or false positives and false negatives.
Therefore, there is a need to prevent the above mentioned potential problems associated with implantable sensors that are sensitive to a patient's body position and/or body movement.
Sensors, such as accelerometers and position sensors are available for detecting body movement and/or body position. Typically, accelerometers provide feedback regarding a patient's activity level, so that pacing rates can be adjusted to meet the metabolic demands of the body. Since these sensors are already incorporated into many implantable devices, it would be beneficial and relatively simple to use them for additional purposes.